We have demonstrated that the phorbol ester TPA is capable of causing induction of immunoglobulin synthesis in chronic lymphocytic leukemia cells (CLL). This induction involves increased levels of mRNA coding for the secretory form of IgM. Our goal in this study is to discern the mechanism(s) whereby TPA exerts its effects on these CLL cells. We have now expanded these studies to include the mechanisms iby which immunoglobulin secretion normally occurs.